Process of producing insulating sheets



R. KARG ET AL.

April 1, 1930.

PROCESS OF PRODUCING TNSULATING SHEETS Filed Sept 27, 1.927

Patented Apr. 1, 1930 UNITED STATES PATENT OFFICE raoonss or rnonucnvo msurarme snnnr's Application filed September 27, 1927, Serial No. 222,308, and in Switzerland October 4, 1928.

This invention consists in a process of producing insulating sheets by the utilization of a fibrous, vegetable material, for example wood wool, shavings, rushes, straw and so 5 forth, and magnesite. 3

The process is characterized in that the fibrous material with addition of magnesite is saturated with an aqueous solution of a product which has the property of binding with the magnesite, allowed to drain, laid in perforated moulds and dried.

Kies'erite, bitter salt, Glauber salt and so forth may be employed as the substance for binding of the magnesite.

The magnesite can be added to the solution of the products with which it binds or it can be added in dust form to the vegetable material treated with the solution.

The moulds may for example consist of a frame with a perforated bottom I of wire web, a stretching net, a sieve and so forth, which is closed with a cover which may also be perforated. V

The drying of the sheets can take place in in the air or in special drying ovens.

The erforation'of the mould has the purpose o facilitating the esca e of the vapours which develop durin the rying out.

i To. produce such pl ates, kieserite 1s for exam le dissolved in water, then some magneslte is added to this solution and wood wool is then dipped in, removed, allowed to drain, placed in moulds and thereupon dried.' Furthermore the same solution can be prepared, the wood wool dipped m, drawn out and dusted with magnesite, laid in th moulds and dried therein.

The sheets soproduced can be covered on one or both sides with a layer of cement, gypsum, artificial wood and the like. To this end, this material is applied in the manner of plaster or the insulating sheet is placed in a fresh mould which is partly filled with this covering material and the sheet is taken out after the covering has hardened.

' y In order to strengthen the insulating plate, the same may be reinforced, for exam ple with wood laths. To this end these laths are embedded in the fibrous material and the material is allowed. to harden in the moulds.

The plates can also be provided on the smaller sides with grooves and tongues by providing corresponding cavities in the moulds.

These tongues and grooves may also be provided on the outer reinforcing strips by correspondingly profiling these strips.

Furthermore the grooved and tongued edges can be formed of casein glue or other suitable glue or cement, by filling the moulds having correspondin cavities with the glue or cement at the e ges and stamping the fibrous material inside thesame.

Uonstructional examples of such covered plates are illustrated in the accompanying drawings, wherein-- Figures 1, 2 and 3 respectively show such a plate without reinforcements, in edge view, 10 face view and cross section.

Figures 4, 5 and 6 show similar views of a reinforced plate in which the covering is also provided with a profile and in which both of the outer reinforcing strips are provided with a slot and key.

Figure 7 is a cross section showing a part of a plate in which the edge consists of artificial wood for the reception of the slot or keyi so eferring now more particularly to Figures .1, 2 and 3, 1 designates a sheet, plate or board, such as wallboard, provided with a hardened plastic insulating sheet or facing '2 embodying my invention and which ma 8 be provided on its outer surface-with a bee ing or other ornamentation 5. As shown, the boards may be provided with inter-engaging grooved and tongued edges 3 and 4. In the form of the invention shown in Figures 4, 5 and 6,-the boards 1 are provided with reinforcing members such as laths 6, embedded therein, the laths at the edges of the boards being provided with tongues 7 and grooves '8. Figure 7 shows a construction in which 96 the marginal edge 9 of the board, in which the groove 10 of a coacting tongue, is formed, is made up of casein glue or other suitable glue or cement, as herembefore described.

An objection to insulating sheets or facings zoo of the kind commonl in use is that many of these embody a binding material containing chlorine or constituted so that the material does not adhere firmly and ermanently to the board. It has heretofore can found articularly difiicult to find a binding medium which is suitable for use with ma nesite and at the same time will provide a rm binder of the elements of the plastic composition forming the sheet or facing and adapt the latter to adhere firmly to the wall board. By the use of kieserite these objections are overcome and a binder provided, which is highly eflicient for use in compositions containing magnesite and causes such compositions to adhere with great tenacity to the wall board. Kieserite is greatl superior to Epsom salt, as while it is solu le in hot water, it is not, like Epsom salt, soluble in cold water, and hence acts to a desirable degree as a waterproofing agent. Kieserite is also very cheap and the drying" process is much more rapid with it than where Epsom salt, sulphate radical or other binders are used.

Havin now particularly described and ascertaine the nature of our said invention and in what manner the same is to be formed, we declare that what we claim 1s- 1. A process for roducing insulating sheets, which consists in placing a vegetable fibre in a solution of kieserite and magnesite and causing said fibre to take up a proportion of the solution, removing the fibre from the solution and draining therefrom any surplus solution, and moldin the sheet from the so treated fibre in a mo (1 perforated to permit evaporation of the moisture in the fibre.

2. A molded insulating sheet formed from a vegetable fibre which has been subjected to the action of a solution of kieserite and magnesite and molded therefrom.

In testimony whereof they aflix their signatures.

RUDOLF KARG. JOSEF WEISS.

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